Transmission system.



C. L. GOODRUM. TRANSMISSION SYSTEM.

APPLICATION FILED OCT. 3, 1915.

Patented` Jan. 8, 1918.

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lvl m CHARLES L. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, T

WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TRANSMISSION SYSTEM.

Specication of Letters Patent.

'Patented aan. s. yreis.

application area october a,` 19,15. Hsemi no. 54,740.

' ing at New York, in the county of New York and State of New York, have invented certain new' land-useful' Improvements in Transmission Systems, of which the following is afull,rclear, concise, and exact description.

This invention relates to a system for establishing communication between a moving train and a central oi` despatchers station,

and is particularly applicable for such purpose where the block signaling system is in force.

In accordance with this invention there is provided a comparatively inexpensivewireless equipment on each train. An aerial conductor paralleling the track is located in convenient proximity thereto. This conductor is divided into sections preferably corresponding to the number of block sections. Each of these sections is adapted to be connected inductively to a balanced pair of wires by the closure of a contact controlled by a semaphore signal, which is actuated upon the entrance of a train into a given section. ImpulsesV sent out by wireless are communicated to a given section of the aerial conductor, which effects the transmissionv thereofover the balanced pair of wires to the central or despatchers oiiice.

The object of this invention is to provide means whereby it is possible to communicate with a moving train partly by wireless and partlyby the agency of metallic conductors,

thereby making tli'c despatching of trains, while in motion, reliable and commercially possible.

At the present time it is possibleto communicate with a moving train from a central station bymeans of wireless apparatus. However, this has not been successeful from a commercial standpoint because it is necessary to equip each train with a very expensive wireless apparatus in order tol obtain anything like ancective range of transmission; also when a train enters a tunnel, communication therewith is seriously interfered with, if not impossible, for reasons well known to the art of wireless telephony.

It has also been proposed to establish communication between a moving train and a despatchers oilice by static induction track, caused by foreign sources of current having an inductive effect upon said conductor, reached a considerable magnitude due to the length of said conductor.

The accompanying drawing illustrates diagrammatically one of the arrangements by whichthis invention may be eli'ectuated.

In the drawing there is shown a vehicle or car` l adapted to travel over track rails 2. lThe roadbed is divided into sectionsf3, 4 and 5, as is usual when a block signaling system is in force. Located at each track section is a signaling mechanism 6 provided with a semaphore 7 which-mechanism may be of any standard well-known construction which is adapted to be actuated by the passing of a car over the section controlled by a particular one of said mechanisms. Paralleling the track rails and located in close proximity thereto is an aerial conductor 8, preferably having bothv of its-ends ounded. The conductor 8 is inductive y connected by means of an inductorium 9 to a balanced pair of wires 10, which extend along the roadbed and to a central office. At the central oilice there is located apparatus for transmitting and receiving telephonic messages. This apparatus which is shown within the dotted rectangle 14 is of the type disclosed in Fig. 1, of the De Forest Patent No. 1,042,205, the ground and aerial ends of the antenna As thereof being connected respectively to the line conductors 10.

Since this transmitting and receiving apparatus is fully described in the De Forest patent, further description here is considthe track, by virtue of the Wireless equip- 2i i fore referred to.

The operation of the transmission system contemplated by this invention may best be understood by assuming that the car 1 has passed from section 4 into section. 3, and upon the passage of said car into section 3 the block signaling mechanism 6 .Was actuated, thereby causing the semaphore 7 to effect the closure of a contact 11.i This places the aerial conductor-8 in inductive relation with the central station or despatchers office by means of the balanced pair of Wires 10. As the car 1 travels along ments 12 -carried thereby, electrical impulses may be transmitted to the conductor 8, which are conveyed to the despatchers oflice over the balanced pair ofwires, and there translated by suitable message-receiv' ing apparatus. Messages may be transmitted from the despatchers oiice to the car in the same manner, only in the reverse order.

From the abpve it will be seen that in accordance with this invention a message may be transmitted to a' moving train partly by Wireless and partly by Wire. The object of dividing the aerial conductor 8 into sections corresponding to the block sections is to overcome any objectionable noise which may be induced on conductor 8 by foreign sources of current, which ordinarily come into close proximity thereto at various places along 'the railway, and if such conductor Was continuous instead of being sectional, the magnitude of these induced noises Would be considerable upon a long conductor. Having the conductors 8 divided -into sections and inductively .connected toa balanced pair of Wires substantially eliminates any; noises Which may be picked up in the' manner just described.

In View of the above it Will be apparent that the Wireless apparatus 12, carried by the car 12 need not have a large range of transmission, thus considerably reducing the cost of similar apparatus'in systems Where communication is established entirely by Wireless. At thesame time the range of transmission of the Wireless apparatus 12 will be suiicient to permit the location of the conductor 8 at a convenient distance from the track rails 2, so as not to interfere with the operation of trains on the railway system. By virtue of the transmission qualities of the Wireless apparatus 12, electrical impulses may be transmittedy a greater distance through space than is possible by a means of static induction.

What is claimed is: 1. In a transmission system, the combination with a block signal mechanism having a-semaphore arranged to be actuated by the passage of a carover the track section governed' by said mechanism, of an aerial conductor paralleling said track and in close proximity thereto, a car or vehicle traveling on said track section, means carried by said car for impressing electrical impulses upon said conductor, and means for conveying said impulses to a central office, said means including a balanced pair of wires extending along the track and having their circu-it normally opened at a contact controlled by said signal mechanism.

2.v In a transmission system, the combination with a block signal mechanism having a semaphore arranged to be actuated by the passage of alcar over 'the track section l governed by said'mechanism, of an aerial conductor paralleling said track and in close proximity thereto, a car or vehicle travel'- ing on said track section, means carried by said car for impressing electrical impulses upon said conductor, and means for conveying said impulses to a central oflce, said means including a balanced pair of vWires extending along the track from a central station, said Wires being in`ductively connected. to -said conductor, and means con-` trolled by said semaphore for interrupting the circuit of said balanced wires.

3. In a transmission system, the combination with a block signal mechanism having a semaphore arranged to be actuated by the passage of a carover the track section governed by said mechanism, of a balanced pair of Wires adapted for telephone purposes extending along the track from a central station, said Wires being associated With said signal mechanism and having their circuit 195 normally opened, a contact controlled by said semaphore for closing the circuit of said Wires, a car or vehicle travelin on said track section, said car being, furnis ed with a Wireless equipment, an aerial conductor 11g paralleling said track and in close proximity thereto, said conductor being inductively 'connected tor said balanced pair of Wires whereby communicating may be established between said car and said station upon the closure of said contact.

4,. In a transmission system, thecombina- 'tion with a plurality of block signal mechanisms each having a semaphore arranged to be actuated by the passage of a car over the 12@ track section governed by a given one of said mechanisms, of a balanced pair of Wires adapted vfor telephone purposes extending along the track from a central station, said Wires being associated with said signal mechanism and having their circuit normally opened, means individual to each of said semaphores for closing the circuit of said wires, a car or vehicle traveling on one of said track sections, said car being furmeme? nished lwith a wireless equipment, an aerial may be established between said car and conductor paralleling said track and in close said station upon the closure of any of said proximity thereto, Said conductor being dicontacts. .1@ vided into sections corresponding in number In witness whereof, I hereunto subscribe 5 to said signaling mechan1sm,said conductor my name this 5th day of October, A. D.

being inductively connected to said bal- ,1915. l anced pair of wires whereby communication CHARLES L. GOODRUM. 

